Bugfix: control comments next to other comments not detected

Addresses further issues documented in #150 by @acdha

Allows:
```
.foo {
    // Keep the footer anchored on short pages using increasingly accurate/un-supported calculations:
    // scss-lint:disable DuplicateProperty
    min-height: 100%;
    min-height: 90vh;
    min-height: calc(100vh - #{($navbar-height * 2) + $navbar-padding-vertical});
}
```
to lint correctly.